痴呆の重症度と脳幹聴性誘発電位—頂点潜時と頂点間潜時について

The Severity of Dementia and Brainstem Auditory Evoked Potentials : Peak Latency and Interpeak Latency

　痴呆の重症度と脳幹聴性誘発電位（BAEPs）の各潜時との関連について検討した。対象は痴呆性疾患80例（男子20例，女子60例）で，平均年齢は80.7±6.7歳であった。正常対照群は，痴呆のない正常高齢者9例（男子2，女子7例）で，平均年齢は80.4±7.4歳であった。計測したBAEPsのパラメーターはI・III・V波の頂点潜時（PL），I-III・III-V・I-V頂点間潜時（IPL），V PLとI-V IPLの両耳差（VPLDs・I-VIPLDs）であった。性差および臨床的事項については，①III・V PLとIII-V・I-VIPLに有意な性差が認められた。②血管性痴呆と変性疾患性痴呆（アルツハイマー型およびパーキンソン病性痴呆）のVPLDsに有意差が認められた。罹病期間とBAEPsの各潜時との間に関連はなかった。

　BAEPsの性差を考慮して，女性痴呆患者を重症度別に軽度痴呆，中等度痴呆，高度痴呆の3群に分け正常女性高齢者（正常者）と比較検討すると，③痴呆の重症度につれて，III・V PL，I-III・II-V・I-V IPL，VPLDsが延長していた。

　以上の結果は，脳幹障害が痴呆の重症度につれて進行することを示唆している。

We have examined the correlation of dementia severity and brainstem auditory evoked potentials. The subjects were 80 patients with dementia (20 males, 60 females) whose mean age was 80.7 years. Normal controls were 9 elderly subjects (2 males, 7 females) whose mean age was 80.4 years. The following parameters were measured : peak latencies ( I , III and V), interpeak latencies ( I -III, III- V and I - V) and interaural latency differences (V PLDs and I - V IPLDs).

As for clinical items and sex differences ; ① There were sex differences recognized between peak latency of III and V, interpeak latency of III-V and I -V. ②There was a significant difference in interaural differences of V PL Ds between vascu-lar dementia and degenerative dementia (dementia of the Alzheimer's type and Parkinson's disease). Duration of illness had no correlation with latencies of BAEPs.

Dividing the patients into three groups according to the severity of dementia which are mild, mode-rate and severe, ③ peak latency of III, V and inter-peak latency of I -III, III- V , I -V and interaural latency diferences of V PL Ds prolonged signi-ficantly with the increasing severity of dementia.

From these results, it is suggested that brainstem dysfunction progresses with the increasing severity of the dementia.